Such clutch units, which are also called twin clutches, have become state of the art, e.g. through U.S. Pat. No. 3,760,918, U.S. Pat. No. 5,513,734, or U.S. Pat. No. 4,465,170.
Such clutch units are being used in agricultural tractors or agricultural machinery among other applications. Thus one of the clutches is used for driving operations, and the other clutch is used for turning an additional drive on and off, through which additional equipment can be driven. Such additional equipment can be e.g. pumps, equipment to work the soil, harvesting equipment, or processing equipment for the harvested material.